Electric switch or switch-fuse unit



April 14, 1953 w. SHARP 2,635,151

ELECTRIC SWITCH OR SWITCH-FUSE UNIT Filed Aug. 5l, 1950 2 SHEETS-SHEET l WlZZz'alz A* 71,17

. y B y m Attorney).`

April 14, 1953 w. SHARP ELECTRIC SWITCH OR SWITCH-FUSE UNIT Filed Aug. 3l, 1950 2 SHEETS--SHEET 2 f, ","NHI

Invenor Attorney.

Patented Apr. 14, '1953 ELECTRIC SWITCH R SWITCH-FUSE UNIT William Sharp, Kings Norton, Birmingham, England Application August 31, 1950, Serial No. 182,547 In Great Britain September 2, 1949 2 Claims. (Cl. 200-50) This invention relates to electric switches having movable contacts in the form of cartridge fuses and it has for its object the provision of a new or improved switch or switch-fuse unit which is simple in construction, inexpensive to manufacture, and efficient in operation. A further object is to enable the entire set of fuse cartridges of the switch to be removed for inspection and replacement. A still further object is to mount and support the fuse cartridges so that the end caps will not be broken away from a glass tube forming the body of the cartridge. Further objects of the invention are to minimise arcing between the fixed and moving contacts of the switch or switch-fuse unit and to ensure that the faces of the said contacts are self-cleaning.

Referring to the drawings:

Figure l is a sectional plan View of a switch constructed according to this invention, the section being taken on line I-I of Figure 2.

Figure 2 is a section on line II-II of Figure 1 looking in the direction of the arrow.

Figure 3 is a section on line III-III of Figure 1 looking in the direction of the arrow.

Figure i is an end view of the switch casing showing the switch lever removed.

Figure 5 is an inside face view of the switch lever.

Figure 6 is an inside face view oi' a clamping bar of the moving contact carrier, and

Figure 7 is a face View of a socket or cap holding fuse carrier bars.

According to a convenient embodiment of this invention, the switch comprises a switch box I and the fixed contacts 2 to be bridged by the cartridge fuses 3 are nlounted on electric insulating bars d. xed to the bottom of the box. The iixed contacts 2 comprise L -shaped copper strips, one arm of which is fixed to the insulating bar, whilst the other arm has a substantially trough or triangular shaped contact tip 5a, the contact tips being thus spring supported as the Contact strips form spring arms. in this particular embodiment, three xed contacts are xed on one insulating bar and three oppositely arranged contacts are fixed on the other insulating bar 4. The electric wires of each electric circuit are connected to opposite contacts and until such pair of contacts are bridged the circuit is broken. The center portion of the movable contact carrier A comprises two half portions or bars 5 which have transversely arranged trough shaped grooves fia for receiving bridging contacts in the form of cartridge fuses L. The cartridge fuses are of the usual construction comprising metal caps mounted on a cylinder of glass and connected by a fusible electrical conducting wire. The trough-shaped grooves are enlarged at each outer end for receiving the cartridge fuse caps to form shoulders for engaging the inner edge of each fuse cap, thereby locating the cartridge fuse centrally of the bars with a portion of a fuse cap projecting from each opposite face or the carrier A. Thus only the correct cartridge fuse 3 can be fitted in the carrier. The two bars 5 are detachably held in the position clamping the fuses 3 by means of end caps or sockets, one cap 8 having a trunnion pin 8 projecting therefrom for engaging a hole in a flange of the switch cover S. The said caps or sockets are made from a sheet metal plate on which the trunnion pins 8 and I8 respectively are fixed and the walls of the sockets are formed by bending up anges 6c from the said metal plate, the anges @a being free to fit in the bars 5. The other end cap l is permanently mounted in the boss la on the opposite flange Il] of the cover, and the carrier parts are held together and in vposition on the cover by means of a helical spring II on the trunnion of the slidable carrier cap 6, which spring is compressed between such cap 6 and the inner face of the flange or the cover. The carrier caps 5 and 'I are conveniently oblong and the carrier A correspondingly shaped so that the carrier will always be replaced in the correct position. The carrier is given a snap-action control conveniently by means of a pin I2 rotatably mounted on a bracket I 5 on the permanently mounted cover cap i and passing through a hole in a bracket I3 fixed to the cover, a helical spring i4 being mounted on the pin and being located between the bracket and the pivoted end of the pin. The bracket i5 limits the movement of the carrier in one direction by moving against a pin I'I, whilst the movement in the other direction is limited by the bracket I5 moving against a pin I6, the pins i6 and II being on the cover 9. The dead centre position of the snap-action control may be arranged to give either a ouick make and break or a slow break. The spindle or trunnion pin I8 on the permanently mounted carrier cap is iitted with an operating lever I9 having a notch 2i? which engages a cross pin 2| on the trunnion pin I8 to provide for the reouired lost motion in the make or break. rlhe switch lever is adapted to engage a projection 22 on the box so that when the switch is in the on position, the switch cover is locked in position, and when the switch is in the off position the cover is free to be removed. F'or this purpose a tail piece on the lever is provided with a circular flange 23 which encartridge fuse and can be readily replaced as itV is only necessary to remove the cover andv detach the carrier. lThe carrier engages the cartridge fuse caps so that the cartridge fusesarev not likely to be mechanically damaged. I'he bridge contact for the neutral may be a solid bar.

Having thus described the invention, what is claimed as new and desired to be secured by Letters Patent is:

i. An electric switch comprising a box for enclosing Contact members oi the switch, xed con.- tact members each comprising a springv blade mounted in the box on opposite sides' thereof, contacts in the forni of cartridge fuses having end caps for bridging said fixed contact members, a displaceable lid for the box, a carrier for said bridging contacts rotatably and detachably mounted in the said lid and located between said fixed contacts when the lid is on the box and adapted tomove the bridging contacts into or out of bridging position,- and comprising. a centre portion divided longitudinally intoV two half por-jtions, grooves in each longitudinal half. with the grooves in one halt portion registering with the grooves in the other half portion to` clamp the caps of said cartridge fuses therebetween, socket members having trunnionsA rotatably mounted on opposite sides of said lid for detachably receiving and iixing together the said parts of the centre portion of the carrier, a lever mounted on one oi trunnion pins` on a said socket mem-ber for moving said carrier into position. bridging the i'ixed' contacts or out of suoli` position, and means on the box interlocking the said lever when'the switch contacts are closed to` prevent the displacement of the lid until the switchcon'tacts are Openn 2. An electric switch comprising a box for enclosing contact members of the switch, fixed contact members each comprising a spring blade mounted in the box on opposite sides thereof, bridging contacts in the form of cartridge fuses having end caps, triangularl shaped tips on said spring blades for pressing on the end, faces of the caps of the cartridge fuses, a displaceable lid ior the box, a carrier for said bridging contacts rotatably and detachably mounted in the said lid and located between said fixed contacts when the li'd is on the box and comprising a centre portion divided longitudinally into two half portions,

, grooves in each longitudinal half with the grooves in` one na-lf portion registering with the grooves inthe other half portion to clamp said caps of the cartridge fuses therebetween, a socket member having a trunnion pin rotatably mounted on one side of. the lid and adapted to receive said parts Y ofthe centre portion of the carrier to hold such parts together at one end`,.a socket. member havm ing a trunnion pin rotatably and slidably mount ed on the opposite side of said lid and engaged on the other end of said centre portions of the carrier by sliding the socket on saidv trunnion pin, a lever vmounted onthe pin on the rstl mentioned socket member for moving the same into position, and means on the box interlocking with said lever when the switch contacts are closed to prevent the displacement of the lid until the switch contacts are operi WILLIAM SHARP.

References Cited in the le of this patent UNITED STATES PATENTS Great Britain Feb. 24, 1927 

